I am set with grace sdac, all I miss is changeable digital filters. Default one is not slow roll-off which is a must for my preferences for classical recordings to handle transients exceptionally fast. Maybe I will check out chip spec and mod it to communicate with DAC chip on the bus to be able to switch filters - for me it would be end of the road dac. I would pay even 2-3x for grace if they do it within this small, lovely box.
A few days ago was checking out X1S as DAC only (because built-in amp was step aside from atom performance IMHO) and I was like changing digital filters during playback 5 times. I figured It was always set to 2nd filter - I was not sure which one is that, but after I got home and checked specs just out of curiosity, it was of course slow roll-off. It gives a bit sparkle, speed and aggressiveness instead of being smoothed out and boring. Must be something with it, because I can easily detect which filter it is or at least if it's slow roll-off or not with almost 100% probabilty during AB tests.
It would be interesting to see if you could guess which filter (fast or slow roll-off) was used with D10 as Topping didn't specified.
My guess, based on logic, not hearing, is that it's fast but I'm really not sure.